Respiratory System Overview

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Questions and Answers

Which of the following structures is NOT part of the upper respiratory tract?

Nasal cavity

Pharynx

Nose

Larynx (correct)

Which of these is involved in transporting, filtering, humidifying, and warming air?

Respiratory bronchioles

Alveoli

Bronchioles (correct)

Alveolar ducts

The structures of the respiratory system are divided into which two main sections?

Respiratory tract and conducting tract

Respiratory tract and respiratory system

Respiratory tract and circulatory tract

Upper respiratory tract and lower respiratory tract (correct)

What is the main function of the respiratory zone?

Exchanging oxygen and carbon dioxide (D) Signup and view all the answers

Which of the following is NOT part of the conducting zone?

Respiratory bronchioles (B) Signup and view all the answers

Which of the following muscles are responsible for controlling the tension on the vocal folds and opening the glottis?

Intrinsic muscles (C) Signup and view all the answers

What does the carina of the trachea trigger?

Cough reflex (A) Signup and view all the answers

What type of epithelium lines the trachea?

Pseudostratified epithelium (C) Signup and view all the answers

What is the main function of the C-shaped cartilage rings in the trachea?

To prevent the trachea from collapsing (B) Signup and view all the answers

What is the primary function of the goblet cells in the trachea?

To produce mucus (A) Signup and view all the answers

Why is the right primary bronchus more likely to be obstructed by a foreign object than the left primary bronchus?

All of the above (D) Signup and view all the answers

At what level does the trachea divide into the left and right primary bronchi?

At the level of the 5th thoracic vertebra (D) Signup and view all the answers

What happens to the air that reaches the bronchi?

It is filtered, warmed, and humidified (A) Signup and view all the answers

Which of the following structures is responsible for dividing the nasal cavity?

Nasal septum (C) Signup and view all the answers

What is the main function of the conchae in the nasal cavity?

Increasing surface area for air flow (D) Signup and view all the answers

Which of the following structures is NOT part of the pharynx?

Epiglottis (C) Signup and view all the answers

Which type of epithelium is found in the nasopharynx?

Pseudostratified columnar (C) Signup and view all the answers

Which of the following cartilages is NOT paired in the larynx?

Thyroid (C) Signup and view all the answers

Which of the following structures is responsible for the production of sound?

True vocal cord (C) Signup and view all the answers

Which of the following is NOT a function of the respiratory system?

Digestion (A) Signup and view all the answers

Why is the respiratory membrane important?

It's the primary site of gas exchange between air and blood (C) Signup and view all the answers

Which of the following statements is TRUE about the larynx?

It protects the glottis (A) Signup and view all the answers

Signup and view all the answers

Study Notes

Respiratory System Learning Outcomes

Students will understand the anatomy of the respiratory system.
Students will understand the function of the respiratory system.
Students will understand the process of gas exchange and gas transport.
Students will understand the regulation of respiration.

Respiratory System Divisions

The respiratory system is divided into the upper and lower respiratory tract.
The upper respiratory tract includes the nose, pharynx, nasal cavity, and paranasal sinuses.
The lower respiratory tract includes the larynx, trachea, bronchi, bronchioles, and alveoli.

Conducting Zone

The conducting zone consists of structures that transport air.
These structures do not participate in gas exchange.
These structures include the nasal cavity, nasopharynx, oropharynx, laryngopharynx, larynx, trachea, bronchi, and all bronchioles except for respiratory bronchioles.
They are responsible for transporting, filtering, humidifying, and warming air.

Respiratory Zone

The respiratory zone includes structures where gas exchange occurs.
The sites of gas exchange are called alveoli (singular: alveolus).
All respiratory zone structures contain alveoli, including respiratory bronchioles, alveolar ducts, and alveolar sacs.

Nasal Cavity

The nasal septum divides the nasal cavity.
The hard palate forms the floor of the nasal cavity and separates it from the oral cavity.
Bony ridges called conchae increase the surface area of the nasal cavity, causing air to churn.

Paranasal Sinuses

Paranasal sinuses open into the nasal cavity and are lined with mucous membranes.
Nasolacrimal ducts connect the eyes to the nasal cavity.
Olfactory receptors are located in the superior part of the nasal cavity.
Lining of the cavity is with stratified squamous epithelium and coarse hair to trap dust or large particles.
Near the pharynx, the cavity is lined by pseudostratified columnar cells associated with goblet cells for a sneeze reflex.

The Pharynx

The pharynx is shared by the digestive and respiratory systems.
It is divided into three sections:
Nasopharynx (pseudostratified columnar – superior portion ; enclosed by uvulva during swallowing)
Oropharynx (Stratified squamous) – continuous with the oral cavity
Laryngopharynx – from tip of epiglottis until esophagus

Trachea

The trachea extends from the larynx to the mediastinum, dividing into left and right primary bronchi at the 5th thoracic vertebra.
The trachea is lined by pseudostratified epithelium associated with goblet cells to secrete mucus due to abundant seromucous glands.
It is supported by 16-20 C-shaped hyaline cartilage rings.
The posterior wall of the trachea has no cartilage, is of connective tissue and smooth muscle, enabling it to contract during coughing.
The trachea provides the esophagus with space to expand when large food boluses are swallowed.
The last tracheal cartilage is expanded and contains a sensitive projection known as the carina.
The mucous membrane in the carina is the most sensitive area of the larynx and trachea, triggering the cough reflex.
The right primary bronchus is more vertical, shorter, and broader than the left.

Bronchi

The trachea divides into two main bronchi, right and left.
The right bronchus is wider, shorter, and more vertical than the left, making it more prone to foreign object obstruction.
The bronchi are lined by pseudostratified columnar epithelium and supported by C-shaped cartilage.
Air reaching the bronchi is filtered, warmed, and humidified.

Bronchial Tree

The main bronchi divide into lobar (secondary) bronchi.
The right lung has three lobar bronchi, one for each lobe.
The left lung has two lobar bronchi.
Lobar bronchi divide further into segmental (tertiary) bronchi, creating smaller and smaller bronchi (approximately 23 branchings).
Tertiary bronchi supply air to a single bronchopulmonary segment.
Passageways with a diameter less than 1 mm are called bronchioles.

Bronchioles

Terminal bronchioles are the last bronchioles without alveoli.
Bronchioles with alveoli are called respiratory bronchioles and lead into alveolar ducts.
Cartilage is absent in the walls, and smooth muscle increases with branching, allowing for relaxation and contraction to control air passageway diameters.

Lungs

Lungs consist of lobes separated by fissures. The right lung has three lobes, the left lung has two.
The left lung has a concave medial surface with a cardiac notch.

Alveolar Ducts and Alveoli

Respiratory bronchioles terminate in alveolar ducts and sacs (respiratory membrane), each with many openings into alveoli, small air sacs.
The respiratory membrane consists of a thin layer of fluid, alveolar epithelium (squamous epithelium), basement membrane, interstitial space, basement membrane of capillary endothelium, and capillary endothelium (squamous epithelium). Six layers total.

Alveolar Cells

Alveolar cells (Type I pneumocytes) line the alveolar surface.
Septal cells (Type II pneumocytes) secrete surfactant to reduce surface tension.
Alveolar macrophages (dust cells) engulf foreign particles.

Pleural Cavities and Membranes

Each lung is enclosed by a pleura, which is a serous membrane.
The pleura consists of two layers:
Parietal pleura: lines the walls of the pleural cavity.
Visceral pleura: adheres to the surface of the lungs.
Pleural fluid fills the space between the pleura, lubricating them for movement with little friction.

Pressure Changes During Inhalation and Exhalation

Intrapulmonary pressure, the pressure inside the lungs, and atmospheric pressure together determine airflow direction.
Intrapleural pressure, the pressure within the space between the parietal and visceral pleura always needs to remain lower than alveolar pressure to prevent collapse of the alveoli.

Pulmonary Ventilation

This is the process of moving air into and out of the lungs.
It relies on Boyle's Law: pressure and volume are inversely related.
Changes in the diaphragm and rib cage volume alter pressure, causing air to flow into or out of the lungs during inspiration and expiration.

Respiration

There are 4 processes involved in respiration:
Pulmonary ventilation (moving air into and out of the lungs).
External respiration (movement of O2 from lungs to blood, CO2 from blood to lungs).
Gas transport (Mechanism of moving O2 and CO2 through blood).
Internal respiration (movement of O2 from the blood to the cell interior, CO2 from cell interior to the blood).

Gas Laws in Respiration

Dalton's law describes how individual gases exert pressure in a mixture, proportional to their abundance.
Henry's law explains that the amount of gas dissolved in a liquid is directly proportionate to its partial pressure.

Gas Exchange

Differences in partial pressure drive gas exchange across the respiratory membrane.
Small diffusion distance, soluble gases, large surface area and coordination of blood flow and airflow make gas exchange efficient across the respiratory membranes.

Oxygen Transport

Oxygen is primarily transported bound to hemoglobin in red blood cells (RBCs).
P02, pH, temperature and fetal hemoglobin are factors that affect how much oxygen is carried in hemoglobin.

Carbon Dioxide Transport

Carbon dioxide transport involves plasma dissolution, carbonic acid formation, and binding to hemoglobin to form carbaminohemoglobin.

Respiratory Centers of the Brain

Medullary centers (DRG and VRG) set the pace of respiration rhythmically.
Pons regulate respiratory centers with apneustic and pneumotaxic centers.

Respiratory Reflexes

Chemoreceptors reflex adjust respiration rates based on levels of carbon dioxide, oxygen, and pH.
Baroreceptors reflexes adjust respiratory rates based on blood pressure
Protective reflexes such as cough and sneeze reflexes.
Higher brain centers such as cerebral cortex and limbic system can influence the rate and rhythm.

Voluntary Control of Respiration

Conscious thought can affect the respiratory rate.
Emotional states, through signals from the limbic system, can affect respiration by influencing either sympathetic or parasympathetic nervous system.

Aging and the Respiratory System

The efficiency of the respiratory system decreases with age.
Elastic tissue in lungs deteriorates, reducing lung compliance and vital capacity.
Chest movements, sometimes restricted by arthritic changes, impact respiratory function.
Some degree of emphysema commonly happens.

Respiratory Diseases

Smoking is a major cause of diseases affecting lung function.
Chronic bronchitis, characterized by bronchial edema, chronic, productive cough, and bronchospasm.
Emphysema involves destruction of alveolar walls, lung fibrosis, and air trapping.

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Description

Explore the anatomy and function of the respiratory system with this quiz. Understand the divisions of the respiratory tract and the roles of the conducting zone in air transport. Test your knowledge on gas exchange processes and the regulation of respiration.